JP2018178453A - Tunnel support structure and steel support - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology relating to a tunnel support structure capable of achieving integration with spread concrete as compared with the conventional technology.SOLUTION: A tunnel support structure comprises an arch shaped steel support arranged in the axial direction of a tunnel, installed along a tunnel wall surface and having an H-shaped cross section, a sprayed concrete layer formed between both steel supports adjacent to the axial direction of the tunnel on the tunnel wall surface, and an anchor member projected on the web of the steel support stock and fixed with the sprayed concrete forming the sprayed concrete layer, wherein the anchor member Is buried in the sprayed concrete layer.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a tunnel support structure and a steel support.

The New Austrian Tunneling Method is known as a method of constructing a tunnel. The NATM method appropriately uses the shotcrete, rock bolt, and steel support under the concept of maintaining the stability of the tunnel by effectively using the support capacity and strength possessed by the ground, using the ground support and the steel support as appropriate. It is a construction method to construct an integrated tunnel structure.

  When constructing a tunnel in the NATM method, the installation of an arch-shaped steel support is usually performed according to the procedure described below. First, a sprayer is set near the face, and the face is sprayed primarily with concrete, and when this is complete, the sprayer is withdrawn. Next, a working vehicle provided with an elector for erecting a support near the face is arranged, and an arched steel support is erected by the erector on the tunnel pit wall near the face, and when this is completed, the working vehicle is withdrawn. Next, the sprayer is re-placed on the face, and the built-in tunnel support is embedded, and a secondary spray of concrete is performed to withdraw the sprayer.

  Since the steel support is generally high in rigidity, it is highly effective in preventing collapse and deformation of the tunnel pit wall (ground), and is effective in securing the stability of the tunnel immediately after face digging immediately after erection. Moreover, in recent years, the shotcrete which exhibits strength and rigidity in a short time from spraying has been put to practical use.

Patent No. 3381606

  However, if the steel support and the shotcrete are not sufficiently integrated, it is thought that it will be difficult to achieve a sufficient support effect.

  The present invention has been made in view of the above problems, and an object thereof is to provide a technology related to a tunnel support structure which can achieve integration with shotcrete as compared with the prior art. is there.

  In order to solve the above problems, according to the present invention, an anchor member for fixing with shot concrete is provided in a convex manner on a steel support web having an H-shaped cross section.

More specifically, the tunnel support structure according to the present invention is arranged in the axial direction of the tunnel and is installed along the tunnel wall surface and has an arch-shaped steel support having an H-shaped cross section, and the tunnel wall surface. And a sprayed concrete layer formed between the steel supports adjacent to each other in the axial direction of the tunnel and a web of the steel support which is projected to form the sprayed concrete layer. And an anchor member fixed to the concrete, wherein the anchor member is buried in the shot concrete layer. In this way, fixing of the shotcrete forming the shotcrete layer and the steel support can be sufficiently secured via the anchor member, and the shotcrete layer and the steel support Integration can be achieved sufficiently. As a result, excellent support effects can be exhibited.

  Here, the anchor member may be convexly provided on both sides of the web plate. According to this, it is possible to further secure fixation of the shotcrete forming the shotcrete layer and the steel support.

  The anchor member may be provided on a leg portion of the steel support. As described above, by securing the fixation with the shotcrete in a focused manner for the leg portion of the steel support, the integrity of the steel support and the shotcrete is improved, and the entire area of the web is covered. Thus, the manufacturing cost can be reduced as compared with the case of installing the anchor member.

  Also, the present invention can be specified as a steel support. That is, the present invention is a steel support arranged in the axial direction of the tunnel and installed along the tunnel pit wall and having an H-shaped cross section, wherein the web of the steel support has the shotcrete and the fixing. The present invention is characterized in that the anchor member to be mounted is provided in a projecting manner.

  ADVANTAGE OF THE INVENTION According to this invention, the technique regarding the tunnel support structure which can aim at unification with blowing concrete compared with the past can be provided.

FIG. 1 is a side view of the tunnel support according to the first embodiment. FIG. 2 is a view for explaining the fixing anchor according to the first embodiment. FIG. 3 is a view for explaining a tunnel support structure in the first embodiment. FIG. 4 is a top view of a working vehicle equipped with the elector device of the first embodiment. FIG. 5 is a side view of a tunnel support according to a modification of the first embodiment. FIG. 6 is a view showing a fixing anchor according to a modification of the first embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First Embodiment
FIG. 1 is a side view of the tunnel support 10 according to the first embodiment. The tunnel support 10 is an arched steel support erected along a pit wall immediately after excavation for preventing collapse of the ground that is exposed during tunnel excavation, and has a fixed distance along the tunnel axial direction. It is installed every time. The tunnel support 10 in the present embodiment is formed of an H-shaped steel having an H-shaped cross section. More specifically, the tunnel support 10 is formed in an arch shape by integrally connecting the top ends (upper ends) of the pair of arc-shaped steel supports 10L and 10R. Hereinafter, the steel support 10L is referred to as "left side steel support", and the steel support 10R is referred to as "right side steel support".

The left steel support 10L includes a first main body 111, a first top end joint plate 121, and a first bottom plate 131. The first main body portion 111 is an H-shaped steel composed of a web 111a, a pair of land-side flanges 111b orthogonal to the web 111a, and an inner air-side flange 111c. Further, the first top end joint plate 121 is welded to one end of the first main body portion 111, and the first bottom plate 131 is welded to the other end. The first top end joint plate 121 and the first bottom plate 131 are square steel flat plates and extend in a direction orthogonal to the H-shaped cross section of the first main body 111. Similarly, the right steel support 10R has a second main body 112, a second top end joint plate 122, and a second bottom plate 132. The second main body portion 112 is an H-shaped steel composed of a web 112a, a pair of ground-side flanges 112b orthogonal to the web 112a, and an inner air-side flange 112c. Further, the second top end joint plate 122 is welded to one end of the second body portion 112, and the second bottom plate 132 is welded to the other end. The second top end joint plate 122 and the second bottom plate 132 are square steel flat plates and extend in a direction orthogonal to the H-shaped cross section of the second main body 112. The first top end joint plate 121 and the second top end joint plate 122 are provided with bolt holes through which bolts are inserted, and a nut 15 is screwed to the center bolt 14 inserted into the bolt holes. The first top end joint plate 121 and the second top end joint plate 122 are fastened.

  The code | symbol 2 shown in FIG. 1 is an anchor bolt. The anchor anchor 2 is provided on the left steel support 10L and the right steel support 10R. More specifically, as shown in FIG. 2, the web 111 a of the first main body 111 in the left steel support 10 L and the web 112 a of the second main body 112 in the right steel support 10 R are anchored as anchor members. The anchor 2 is provided in a convex shape. FIG. 2 is a view for explaining the fixing anchor 2 provided in the first main body portion 111 and the second main body portion 112. As shown in FIG. The fixing anchor 2 includes an axial portion vertically provided from the webs 111a and 112a, and a head provided at the tip of the axial portion and having a diameter larger than that of the axial portion. However, the shape of the fixing anchor 2 can be changed as appropriate. In the present embodiment, in the first main body portion 111, the fixing anchors 2 are provided to protrude on both surfaces of the web 111a. Further, in the second main body portion 112, the fixing anchors 2 are provided in a convex manner on both sides of the web 112a.

  FIG. 3 is a view for explaining a tunnel support structure 1 to which the tunnel support 10 in the first embodiment is applied. The code | symbol 3 in FIG. 3 is a primary shotcrete layer. Moreover, the code | symbol 4 is a metal mesh. Moreover, the code | symbol 6 is a secondary blasting concrete layer. The right steel support 10R of the tunnel support 10 is shown in FIG.

  In the tunnel construction method of the present embodiment, after the underground 7 is exposed to the side of the tunnel T by excavating the face 8, the primary concrete is sprayed with the primary concrete by means of the primary concrete. Layer 3 is formed. Thereafter, the above-described arched tunnel support 10 is built on the inner air side of the primary blasting concrete layer 3 along the tunnel pit wall surface. The tunnel support 10 is adjacent to the face 8 with respect to the existing tunnel support 10 located on the wellhead side of the tunnel T, and has a predetermined distance (for example, 1.0 m to 1.5 m) in the axial direction of the tunnel T Degree) are arranged.

The erecting work of the left steel support 10L and the right steel support 10R can be performed using, for example, an elector apparatus 100 as shown in FIG. FIG. 4 is a top view of the work vehicle 200 on which the elector device 100 is mounted. The elector apparatus 100 includes a pair of booms 17L and 17R having the same configuration. The pair of booms 17L and 17R can freely extend and retract, tilt, swing and turn by operation of a drive mechanism attached thereto. Further, a pair of hands 18L and 18R having the same configuration are connected to the tips of the booms 17L and 17R. The pair of hands 18L and 18R can freely rotate and swing by the operation of the drive mechanism attached to them, and can hold the left steel support 10L and the right steel support 10R in a detachable manner, respectively. It can be (held). The erector device 100 holds the left steel support 10L and the right steel support 10R on the pair of hands 18L and 18R and drives the hands 18L and 18R to support the left steel support 10L and the right steel support. The work 10R can be erected at a predetermined erection position. In the construction of the left side steel support 10L and the right side steel support 10R, a flat wooden plate is placed on the excavated upper half plate to compensate for the strength of the ground and adjust the installation height. Then, the first bottom plate 131 (second bottom plate 132) of the left side steel support 10L (right side steel support 10R) is placed on the plate, and the left side steel support 10L (right side steel support 10R) ) To be vertical.

Next, for example, a wedge is inserted between the plate and the first bottom plate 131 (second bottom plate 132) so that a light beam emitted from a laser surveying instrument (not shown) matches the target, or the lower portion of the plate The left steel support 10L and the right steel support 10R are installed on the ground by adjusting the height by digging or the like. Next, the first top end joint plate 121 and the second top end joint plate 122 are fastened by the center bolt 14 and the nut 15 (see FIG. 1).

  Next, the wire mesh 4 was disposed along the surface of the primary blasting concrete layer 3 in the new section (see FIG. 3) between the new tunnel support 10 and the existing tunnel support 10 as required. After that, the secondary shot concrete layer 6 is formed by carrying out the shot construction of the secondary shot concrete. The secondary blast concrete is sprayed to a thickness substantially reaching the inner air side flange 112 c (111 c) located on the opposite side to the ground 7 in the pair of flanges in the tunnel support 10. The wire mesh 4 is disposed to reinforce the secondary shot concrete, and may be omitted when the ground condition is good. Moreover, when using a steel fiber reinforcement | strengthening shotcrete (SFRC) etc., for example as a secondary shotcrete, installation of the metal-mesh 4 may be abbreviate | omitted.

  Here, as shown in FIGS. 1 and 2, the tunnel support 10 in the present embodiment includes the web 111 a of the first main body portion 111 in the left steel support 10 L and the second in the right steel support 10 R. The fixing anchor 2 is installed on the web 112 a of the main body 112. Therefore, in the process of forming the secondary shot concrete layer 6, the fixing anchor 2 provided on the web 111a and 112a of the new tunnel support 10 and the web 111a and 112a of the existing tunnel support 10 are provided. The secondary blowing concrete is sprayed so as to cover the fixing anchor 2 provided, whereby the fixing anchor 2 is buried in the secondary blowing concrete layer 6. As a result, through the fixing anchor 2 embedded in the secondary shot concrete layer 6, the secondary shot concrete and the tunnel support 10 can be sufficiently integrated with each other as compared with the prior art. That is, fixing of the tunnel support 10 and the secondary shot concrete layer 6 can be sufficiently secured, and a stable support structure 1 can be constructed.

  Furthermore, in the tunnel support 10 (left side steel support 10L, right side steel support 10R) in the present embodiment, a structure in which the fixing anchors 2 are provided on both sides of the webs 111a and 112a is employed. Therefore, for both the existing tunnel support 10 and the new tunnel support 10 located at both ends of the new section (see FIG. 3) to which the second shot concrete is to be sprayed, the second shot concrete Can be increased.

Further, in the present embodiment, the secondary shot concrete layer 6 may be formed on the tunnel pit wall surface according to the following procedure. That is, the left steel support 10L and the right steel support 10R are built using the Electr apparatus 100, and the first top end joint plate 121 and the second top end joint plate 122 are fastened by the center bolt 14 and the nut 15. After that, while holding the new tunnel support 10 (the left steel support 10L and the right steel support 10R) by the hands 18L and 18R in the elector device 100, the new tunnel support 10 (the left steel support) Spray secondary blasting concrete around the legs of construction 10L and right-handed steel support 10R) and their surroundings. Then, after the secondary shot concrete sprayed to the leg portion of the new tunnel support 10 develops a predetermined strength, the gripping of the new tunnel support 10 by the hands 18L and 18R in the Electr device 100 is released. , The secondary blasting concrete layer 6 is formed on the whole of the new construction section by spraying the secondary blowing concrete on the remaining part of the new construction section. In the tunnel support 10 in the present embodiment, since the fixing anchor 2 is provided on the webs 111a and 112a in a convex manner as described above, the fixing property with the secondary shot concrete is excellent. Therefore, even if the hands 18L and 18R in the elector apparatus 100 for gripping the newly installed tunnel support 10 are removed in a short time after the secondary blast concrete is sprayed on the legs of the newly installed tunnel support 10, the new installation is performed. It is possible to carry out the work of spraying the second shot concrete to the remaining part of the new section without the tunnel support 10 being inclined or falling down.

  Further, in the tunnel support 10 (left side steel support 10L, right side steel support 10R) in the present embodiment, substantially the entire area (section) along the extension direction of the webs 111a and 112a as shown in FIG. Although the plurality of anchoring anchors 2 are installed throughout, the anchoring anchors 2 may be installed only in a part of the area. Here, the fixing anchor 2 may be provided on at least a leg portion of the tunnel support 10 (left side steel support 10L, right side steel support 10R). As an example, as shown in FIG. 5, the anchor anchor 2 is formed to project from the webs 111a and 112a only on the leg portion of the tunnel support 10 (left steel support 10L, right steel support 10R). Can be mentioned. Improve the integrity of the tunnel support 10 and the secondary shot concrete by securing the fixation of the foot of the tunnel support 10 with the secondary shot concrete (secondary shot concrete layer 6) in a focused manner As compared with the case where the fixing anchor 2 is installed over the entire area along the extension direction of the webs 111a and 112a, the manufacturing cost can be reduced. In the embodiment, the fixing anchors 2 are arranged in two rows along the extension direction of the webs 111a and 112a. However, the arrangement pattern of the fixing anchors 2 is not particularly limited.

  Further, in the present embodiment, the fixing anchor 2 can adopt various shapes. FIG. 6 is a view showing a fixing anchor 2 according to a modification of the first embodiment. FIG. 6A shows an example in which the straight rod-like fixing anchor 2 is provided to project from the web 111a (web 112a) of the first main body 111 (second main body 112). Further, FIG. 6B shows an example in which a bar-like fixing anchor 2 with a hook having a hook provided at its tip from the web 111a (web 112a) of the first main body 111 (second main body 112) is convexly provided. ing.

  As mentioned above, although embodiment and modification of this invention were described, the steel support construction and tunnel support structure which concern on this invention are not restricted to these, It is possible to combine these as much as possible.

DESCRIPTION OF SYMBOLS 1 ... Tunnel support structure 2 ... Anchoring anchor 3 ... Primary blasting concrete layer 4 ... Wire mesh 6 ... Secondary blasting concrete layer 7 ... Ground mountain 8 ... Face 10 ... · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 10 ... 2nd top end joint plate

Claims (6)

Arched steel supports, arranged in the axial direction of the tunnel, installed along the tunnel bore wall and having an H-shaped cross section,
A shotcrete layer formed between the steel supports axially adjacent to the tunnel on the tunnel pit surface;
An anchor member which is provided on the web of the steel support in a projecting manner and which is fixed with the shotcrete forming the shotcrete layer;
Equipped with
The anchor member is buried in the shot concrete layer,
Tunnel support structure.   The tunnel support structure according to claim 1, wherein the anchor member is convexly provided on both sides of the web.   The tunnel support structure according to claim 1, wherein the anchor member is provided on a leg portion of the steel support. A steel support arranged in the axial direction of the tunnel and installed along the tunnel pit wall and having an H-shaped cross section,
An anchor member fixed to the shotcrete is convexly provided on the steel support web.
Steel support.   The steel anchor according to claim 4, wherein the anchor member is provided on both sides of the web in a convex manner.   The steel anchor according to claim 4 or 5, wherein the anchor member is provided on a leg portion of the steel anchor.

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